Contamination & Spoilage of fruits and vegetables.pptx

spoilage of fruits and vegetables, microbial load, food infection, food born diseases and different processing technique to remove them.

1. Contamination & Spoilage of fruits and vegetables

2. CONTAMINATION During harvesting and containers unless these have been adequately sanitized Mechanical damage during transportation Soaking, washing, handling Sweating of products during handling Wooden surfaces Hot water blanching - add thermophilic bacteria Inclusion of decayed Added ingredients - add thermophilic bacteria.

3. Fruits Asepsis 2. Removal of micro organisms 3. Use of heat 4. Use of Low temperatures 5. Chilling 6. CA Storage 7. Freezing 8. Drying 9. Use of preservatives   Preservation Vegetables 1. Asepsis 2. Removal of micro organisms 3. Use of heat 4. Use of Low temperatures 5. Chilling 6. Hydrocooling 7. Freezing 8. Drying 9. Use of preservatives 10. Added preservative 11. Preservation by irradiation

4. SPOILAGE Deterioration of raw vegetables and fruits due to Physical factors Action of their own enzymes Microbial action Mechanical damage . Action of animals, birds, insects. Wounding Bursting Freezing Dessication Other mishandling

5. Microbial spoilage of fruit & vegetable 1. Bacterial soft rot — Caused by Erwinia caratovora , these are fermenters of pectins . Pseudomonas, Clostridium, Bacillus sps have also been isolated from these rots. It results in a water soaked appearance, a soft mushy consistency and often a bad odor.

6. 2. Gray mold rot — Caused by Botrytis. It is favored by high humidity and a warm temperature

7. 3. Rhizopus soft rot — It is caused by sps of Rhizopus Ex: Rhizopus stolonifer . This rot is often soft and mushy. The cottony growth of the mold with small, black dots of sporangia often covers masses of the foods.

8. 4. Anthrachose Usually caused by Collectotrichum lindemuthianum , Collectotrichum coccodes , defect is spotting of leaves and fruits or seed pods.

9. 5. Alternaria Rot  Caused by Alternaria tenuis . Areas become greenish brown early in the growth of the mold and later turn to brown or black spots.

10. 6. Blue mold rot Caused by Penicillium digitatum . Bluish green color spores are produced.

11. 7. Downey mildew - Caused by Phytopthora bremia 8. Watery soft rot- Caused chiefly by Sclerotinia sclerotiorum . Found in mostly vegetables

12.   9. Stem end rots- Caused by Diplodia , Alternaria , Phomopsis , Fusarium . 10. Black mold rot- Caused by Aspergillus niger . Dark brown to black masses of spores of the mold termed “Smut”.

13. 11. Black rot:  Caused by Alternaria , Ceratostomella , Physalospora . 12. Pink mold rot: Caused by pink spored Trichothecium roseum . 

14. 13. Fusarium rots:  Caused by Fusarium sps . 14. Green mold rot: Caused by Cladosporium , Trichoderma .

15. 15. Brown rot:  Caused chiefly by Sclerotinia ( Monilinia fructicola ) sps . 16. Sliminess or souring: Caused by Saprophytic bacteria in piled, wet, heating vegetables.16

16.   Spoilage of fruit and vegetable juices Molds can grow on the surface of acidic fruit juices if juices are exposed to air. The lactic acid fermentation of sugars, mostly by heterofermentative lactic acid bacteria such as Lactobacillus pastorianus, Lactobacillus brevis and Leuconostoc mesenteroides. Acetic acid fermentation- by lactic acid bacteria. E.x. Lactobacillus psatorianus. Slime production- by Leuconostoc mesenteroides, Lactobacillus brevis, and Lactobacillus plantarum in apple juice and by L. plantarum and Streptocooci in grape juice.